If no user specified chip->select_chip() function is provided, code in nand_base.c will automatically set this hook to nand_select_chip(), which in turn depends on chip->cmd_ctrl() hook being valid. Not providing both of those functions in NAND controller driver (for example by mistake) will result in a bit cryptic segfault. Same is true for chip->cmdfunc().
To avoid the above scenario add a check in nand_scan_dent and error out if cmd_ctrl() is not provided. Suggested-by: Boris Brezillon <[email protected]> Suggested-by: Brian Norris <[email protected]> Signed-off-by: Andrey Smirnov <[email protected]> --- Changes since v2: - Check moved to nand_scan_ident drivers/mtd/nand/nand_base.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index ce7b2ca..93f5432 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -3997,6 +3997,15 @@ int nand_scan_ident(struct mtd_info *mtd, int maxchips, if (!mtd->name && mtd->dev.parent) mtd->name = dev_name(mtd->dev.parent); + if ((!chip->cmdfunc || !chip->select_chip) && !chip->cmd_ctrl) { + /* + * Default functions assigned for chip_select() and + * cmdfunc() both expect cmd_ctrl() to be populated, + * so we need to check that that's the case + */ + pr_err("chip.cmd_ctrl() callback is not provided"); + return -EINVAL; + } /* Set the default functions */ nand_set_defaults(chip, chip->options & NAND_BUSWIDTH_16); -- 2.5.5
